So a new DNA-based test, capable of confirming the disease within hours, has arrived in labs around the region at a fortuitous time.
Over the last two weeks, things have not been normal in some chickens in Delaware, Pennsylvania and New Jersey. With avian flu blamed for 22 human deaths in Asia, where it is spreading through poultry at an unprecedented rate, scientists here needed to know fast what was happening to their birds.
The results show the difference a few days can make.
Inspectors arrived at a southern Delaware farm to check a report of increased mortality at 4:30 p.m. on Feb. 5. At 8 a.m. the next day, with the help of DNA testing equipment purchased a year ago, the state was able to announce that it had confirmed avian influenza, that the particular strain was virulent in poultry, and that it was unrelated to the type implicated in Thailand and Vietnam.
The public was reassured that there was no Asian connection. Agriculture officials knew how big a quarantine was needed, and scientists had crucial details needed to start tracing the source of the infection.
"The main difference is that the disease could have spread to a much wider range of farms before we had a handle on it," said Edwin Odor, head of food-product inspections for the Delaware Agriculture Department.
"The ripple effect is just unbelievable," he said. As it is, the outbreak - limited to two growers, whose 85,000 chickens were slaughtered - will probably cost millions of dollars. Had there been a delay, he said, the cost would have been "exponentially greater, by the tens of times."
Pennsylvania officials were uneasily following news of the serious H7 type of avian flu in Delaware when routine screenings from a farm in Lancaster County came up positive.
The antibody test, done monthly on samples collected from 331 growers, will not catch the most recent exposures. Nor will it indicate type or virulence. A positive reading triggers more testing.
